Process and apparatus employing microprogrammed control commands for transferring information between a control processor and communications channels

Firmware generated commands provided by a control store in a microprogrammed communications processor which is coupled in a system including a main memory and a central processing unit control the processing of instructions from the central processing unit, interrupts from the communications channels and servicing of such channels if a channel status change is detected. The firmware also controls the operation of the servicing of such channels by providing a control mechanism by which data is read from or written into the main memory. Further, interrupts which are not handled immediately are handled in a deferred interrupt arrangement.